Flotation of minerals.



R.F.BACON.

FLOTATION 0F MINERALS. APPLICATION FILED AUG. 14, 1914.

Patented May 25, 1915.

RaQrYldQND F. BACQN, 0F PITTSBURGH, PENNSYLVANIA, ASSIG-NOR TQ QlEETALS LEEESEAECH COMPANY, 0F NEW YQRK, N. Y., A. CORPORATIQN 0F MAINE.

FLOTATIQN OF MENEJRATLS.

incense.

Application filed August 14, 1914.

To all wk om it may concern Be it known that l, RAYMOND F. Bacon, a citizen of the United States, residing at Pittsburgh, Allegheny county, State of Pennsylvania, have invented certain new and useful improvements in Flotation of Minerals; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make-land use the same.

The present invention is based upon the discovery that metalliferous sulfids can be separated, by flotation, from the gangue with which they are associated, by means of colloidal sulfur. The metalliierous sulfids may be present in the ore as native sulfids, or they may be present therein as sulfids con verted from native oxide or carbonates by the action of hydrogen sulfid.

in the practice of the invention, ll prefer to produce the colloidal sulfur in situ in the body of ore treated, which ore is in the usual fine state of subdivision (say mesh) characteristic of ores to which flotation processes are applied. To this end, the finely divided ores, slimes, or the like, are introduced into a body of water containing in solution a soluble sulfid. Hydrogen sulfid is available for the purpose, or any other soluble sulfid, inasmuch as, when brought into solution a soluble sulfid other than hydrogen sulfid is immediately hydrolyzed. into the vessel containing the ore and the solution of hyrogen sulfid ll then introduce a reagent which will react with the soluble sulfid to produce colloidal sulfur, such a reagent is sulfur dioxid, which is usually available in the form of waste fumes at metallurgical plants, but which may be obtained from any other suitable source.

it is found to be of advantage to introduce the sulfur dioxid in such proportion as to make the colloidal solution faintly acid, in which condition, a sharper and more complcte separation of the ore from the gangue is usualy obtained. It is also preferable, although not essential, to effect the actual flotation in a separate flotation tank or cell, having the usual provisions for overflow oi the floated particles into a launder and for separate collection of the gangue or taihngs;

more convenient to edect the flotation in the Specification of Letters Patent.

Patented May 25, 1915,

Serial no. 85%,??1.

or partition, thereby assisting in bringing the particles to be separated to the surface of the water under the buoying action of the colloidal sulfur. So also, if desired, the colloid solution, in the tank in which the flotation is taking place, or in advance of that tank, may be vigorously agitated by means of a mechanical stirrer or heater, such as, for instance, a rapidly rotated propeller. Furthermore, if desired, a small quantity of oil may be beaten into the solution, either in the preliminary tank or in the secondary tank, as the case may be, to assist in the recovery. In general, however, it will be unnecessary to employ either the mechanical stirring or beating propeller or agitator, or to employ any oil whatsoever, inasmuch as, in most cases, the colloidal sulfur solution alone will be found amply suliicient to efi'ect the 'desired separation unaided except perhaps by the blowing in of air in the manner hereinbefore referred to.

in the accompanying drawing, l have illustrated, partly in section and partly in elevation, apparatus suitable for the practice of the invention. It will, of course, be un derstood, however, that the invention is not limited to any particular specific form or forms of a paratus.

In the rawing, A indicates a vessel in which the ore and water is received, and which may be provided with a rotary propeller or likestirrer or heater carried by the rotary shaft 6. Suitable pipes (Z, c and j", serve for the admission of the soluble sulfid (for instance hydrogen sulfid), sulfur dioxid, and oil (when the latter is used).

a indicates an outlet pipe leading to a dotation tank or cell D, which may be of any suitable type.

In some instances, the solution of colloidal sulfur may, if desired, be produced before the admission of the ore to be separated into the preliminary mixing tank or into the secondary flotation tank or cell, as the case may be; but, for most purposes, and particularly for convenience and economy of operation, it

"is preferable to produce the colloidal solution simultaneously with or subsequent to the admission of the ore to be treated.

The amount of colloidal sulfur in solution will differ somewhat with the kind and character of the ore treated, and can readily be determined by a simple quantitative test. I may say, however, that in the treatment of oxidized copper ore, reduced to 60 mesh, and transformed by hydrogen sulfid into copper sulfid, it has been found sufii cient to employ a solution wherein the amount of colloidal sulfur present is about .1%, in order to obtain a satisfactory separation. It is, of course, to be understood that the colloidal sulfur which is used in this flotation process in place of oil may be produced in'other ways, as, for instance, by the action of an acid or a thiosulfate or other salt of a polythionic acid. Any known method of preparing a solution of colloidal sulfur may be used; for, in so far as I am aware, the discovery is broadly new that colloidal sulfur is able, in flotation processes, to separate mineral from gangue.

What I claim is:

1. The method of effecting the separation of sulfid minerals from associated gangue,

' which consists in subjecting the mixture, in

a finely divided condition, to the flotation action of colloidal sulfur; substantially as described.

2. The method of effecting the separation of sulfid minerals from associated gangue, which consists in subjecting the mixture, in a finely divided condition, to the flotation action of colloidal sulfur, the flotation solution being faintly acidgsubstantially as described.

3. The method of effecting the separation of sulfid minerals from associated 'gangue, which consists in subjecting the mixture, in a finely divided condition, to the flotation action of colloidal sulfur, the flotation solution being produced by reaction therein between a soluble sulfid and sulfur dioxid; substantially as described.

l. The method of effecting the separation of sulfid minerals from associated gangue, which consists in subjecting'the mixture, in a finely divided condition, to the flotation action of colloidal sulfur,the flotation solution being produced by reaction therein between a soluble sulfid and sulfur dioxid, the

sulfur dioxid being admitted in such excess as to make the solution of colloidal sulfur faintly acid; substantially as described.

In testimony whereof I affix my signature,

in presence of two Witnesses.

RAYMOND F. BACON.

Witnesses:

N. A. PARKINSON, E. B. TELFORD. 

